Duo - Main Processing Unit

This is a MilkV Duo 256 (SG2002 microcontroller), it has 256MB RAM, it has 700Mhz RiscV core and either a 1Ghz RiscV core or a 1Ghz Arm Cortex A53 core, a 25 to 300Mhz 8051 core and a 1 TOPS Tensor unit (TPU). The Ant64 will operate it in RiscV mode. Audio will also go directly from/to the “Jazz” chip.

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The TF card interface (SPI0?) will go to the DeMon chip, which will act as an SD card emulator.

SD1 will go direct to...

Pins 21 to 27 (can be configured as a QSPI NOR Flash interface – they will go direct to the Razz. This way the CPU can communicate with the Razz “gpu” as if it was memory mapped IO.

Duo provides a 100MBPS network port.

The Duo has a fast USB interface.

Slower interfaces will go to the Debug monitor, input controller, audio synthesizer and optional “Network controller”.

The current plan is to have the 700Mhz RiscV core provide the operating system, housekeeping tasks, the “monitor” and the built-in computer languages (BASIC/Action). The 1Ghz RiscV core will provide emulation of various processors to simulate various 8 and 16 bit systems.

When emulating a computer, for example an Amiga A1200. The memory inside the MilkV Duo will be used rather than memory available to the "Razz" chip.

An amiga A1200 has a max memory bandwidth of 28MBytes/sec = 224mbits/sec (a normal amiga is 7Mbytes/sec = 56mbit/sec). With RAM being available to the emulated CPU all the time, it will mean the cpu will emulate as fast as possible.

The simulated GPU in the FPGA will request memory via the MilkV Duo MIPI RX port – which can operate at up to 1.5Gbit/sec and then transmit the requested data through the MIPI TX port – which can operate at up to 2.5Gbit.

There will be a protocol to read from “chip registers” contained in the FPGA by requesting them from the TX port and waiting for them at the RX port.

FRAM256 map (0000000-FFFFFFF)

Start address	End address	Size	Description
0000000	03FFFFF	0400000	4MB SRAM
0400000	07FFFFF	0400000	Reserved
0800000	0FFFFFF	0C00000	Reserved
8000000	FFFFFFF	8000000	128MB SDRAM

Duo pinouts:

Pin	Description	CPU pin	Function
1	GP0 - JTAG TDI	28	WTDI / XGPIOA 28
2	GP1 - JTAG TDO	29	WTDO / XGPIOA 29
3	GND
4	GP2 - JTAG TMS	26	WTMS / XGPIOA 19
5	GP3 - JTAG TCK	27	WTCK / XGPIOA 18
6	GP4 - SD1_D2 - SPINOR1_WP	52	SD1 D2
7	GP5 - SD1_D1 - SPINOR1_HOLD	53	SD1 D1
8	GND
9	GP6 - SD1_CLK - SPINOR1_SCK	56	SD1 CLK
10	GP7 - SD1_CMD - SPINOR1_MOSI	55	SD1 CMD
11	GP8 - SD1_D0 - SPINOR1_MISO	54	SD1 D0
12	GP9 - SD1_D3 - SPINOR1_CS	51	SD1 D3
13	GND
14	GP10 - I2C1 SDA - Razz slave	85	Originally 1.8v, now 3.3v (see J1 pin 13)
15	GP11 - I2C1 SCL - Razz slave	86	Originally 1.8v, now 3.3v (see J1 pin 14)
16	GP12 - UART0 TX - to Jazz	18	UART0 TX / XGPIOA 16 – connected via 4.7k resistor to 3.3v
17	GP13 - UART0 RX - from DeMon	19	UART0 RX / XGPIOA 17 – connected via 4.7k resistor to 3.3v
18	GND
19	GP14 – used for SPI (SD0) slave select?	15	SD0_PWR / XGPIOA 14 (See SD CARD interface!)
20	GP15 – used for SPI (SD0) slave select?	17	SPK_EN / XGPIOA 15

Pin	Description	CPU pin	Function
40	VBUS
39	VSYS
38	GND
37	3v3 EN
36	3v3 OUT
35	Boot switch (1.8v?)	67	GPIO_RTX / XGPIOB 23 – connected via 4.7k resistor to 1.8v
34	Audio out (1.8v?)	4	PAD_AUD_AOUTR / XGPIOC 24
33	GND
32	GP27 (1.8v) ADC1 - VSync interrupt via 3.3v conv	60	ADC2 / XGPIOB 6 / USB_VBUS_DET
31	GP26 (1.8v) ADC0 - HSync interrupt via 3.3v conv	59	ADC1 / XGPIOB 3
30	RUN	38	(originally 1.8v, now 3.3v?)
29	GP22 - Pixel clock input	41	(originally 1.8v, now 3.3v) PWR_GPIO 4
28	GND
27	GP21 - SPINOR_HOLD – NOR interface to Jazz?	20	SPINOR_HOLD / XGPIOA 26
26	GP20 - SPINOR_WP	23	SPINOR_WP / XGPIOA 27
25	GP19 - SPINOR_MOSI	22	SPINOR_MOSI / XGPIOA 25
24	GP18 - SPINOR_SCK	21	SPINOR_SCK / XGPIOA 22
23	GND
22	GP17 - SPINOR_CS	25	SPINOR_CS / XGPIOA 24
21	GP16 - SPINOR_MISO	24	SPINOR_MISO / XGPIOA 23

LED is GP25 is CPU 49 (1.8v? PWR_GPIO 2)

DBG 12 is CPU pin 30 (XGPIOA 30) – To GND via 4.7k resistor

MIC is CPU pin 2 (PAD_AUD_AINL / XGPIOC 23) 1.8v?

USB pinouts:

Pin	Description	CPU pin
	USB DP	69
	USB DM	70

Ethernet pinouts:

Pin	Description	CPU pin	Function
1	RXN	62	XGPIOB 25
2	RXP	63	XGPIOB 24
3	GND
4	TXN	64	XGPIOB 27
5	TXP	65	XGPIOB 26

SD card pinouts:

SDCard	Description	SPI Master	CPU pin	Function
4	VDD		3.3v
5	CLK	SPI0 SCK	6	SD0 CLK / XGPIOA 7
3	CMD	SPI0 SDO (MOSI)	7	SD0 CMD / XGPIOA 8
7	D0	SPI0 SDI (MISO)	8	3.3v
8	D1		10	C
1	D2		11	SD0 D2 / XGPIOA 11
2	D3	SPIO CS	12	SD0 D3 / XGPIOA 12
CD	Switch DET	SPIO CS	14	C
	On Milk V 256M pin 19	15	SD0 PWR EN / XGPIOA 14

J1 (camera) pinouts:

Pin	Description	CPU pin	CPU Description (All 1.8v only)
1	GND	GND
2	MIPI0_DN0 – from Razz	80	PAD_MIPI RX0N / XGPIOC 10
3	MIPI0_DP0 – from Razz	81	PAD_MIPI RX0P / XGPIOC 11/td>
4	GND	GND
5	MIPI0_DN1 – from Razz	76	PAD_MIPI RX2N / XGPIOC 6
6	MIPI0_DP1 – from Razz	77	PAD_MIPI RX2P / XGPIOC 7
7	GND	GND
8	MIPI0_CKN – from Jazz	78	PAD_MIPI RX1N / XGPIOC 8
9	MIPI0_CKP – from Jazz	79	PAD_MIPI RX1P / XGPIOC 9
10	GND	GND
11	SENSOR_RSTN (1.8V)	84	XGPIOC 17
12	SENSOR_CLK (1.8V)	88	XGPIOC 15
13	I2C2_SCL (1.8V)	85	XGPIOC 14 / I2C 2 SDA (See main pin 14)
14	I2C2_SDA (1.8V)	86	XGPIOC 15 / I2C 2 SCL (See main pin 15)
15		NC
16	3V3